Glass panel unit

ABSTRACT

A glass panel unit according to an example of the present disclosure includes a first glass panel and a second glass panel disposed to face the first glass panel. The glass panel unit includes: a seal having frame shape and hermetically binding the first glass panel and the second glass panel together; and a depressurized space surrounded by the first glass panel, the second glass panel, and the seal. The glass panel unit includes spacers between the first glass panel and the second glass panel. The spacers include a macromolecular resin material including molecular chains. Of the molecular chains, the number of molecular chains oriented in an orthogonal direction is larger than the number of molecular chains oriented in a counter direction. The orthogonal direction is a direction orthogonal to the counter direction, which is a direction in which the first and second glass panels face each other.

TECHNICAL FIELD

The present disclosure relates to a glass panel unit.

BACKGROUND ART

A glass panel unit including two or more glass panels stacked with aspace therebetween to form a hermetically closed space and a vacuumcreated in the hermetically closed space is known (see, for example,Patent Literature 1). Such a glass panel unit is also referred to as an“insulated glazing”. Such a glass panel unit is also referred to as a“vacuum insulated glass”. The glass panel unit has high thermalinsulation. In the glass panel unit, maintaining the vacuum isimportant.

It has been proposed that spacers be used to maintain a sufficientthickness for a vacuum space of such a glass panel unit. The spacers areparts interposed between the two glass panels.

In the glass panel unit, the spacers conduct heat between the two glasspanels and thus influence the thermal insulation property of the glasspanel unit. It is therefore desirable to reduce as much as possible thethermal conductivity of the spacers in a counter direction in which thetwo glass panels face each other.

CITATION LIST Patent Literature

-   Patent Literature 1: JP H11-311069 A

SUMMARY

In view of the foregoing, it is an object of the present disclosure toprovide a glass panel unit having reduced thermal conductivity in acounter direction in which glass panels face each other.

To solve the problems, a glass panel unit of one aspect according to thepresent disclosure includes a first glass panel including at least aglass pane and a second glass panel disposed to face the first glasspanel. The second glass panel includes at least a glass pane. The glasspanel unit includes a seal having a frame shape and hermetically bindingthe first glass panel and the second glass panel together, and adepressurized space surrounded by the first glass panel, the secondglass panel, and the seal. The glass panel unit includes a spacerdisposed between the first glass panel and the second glass panel. Thespacer contains a macromolecular resin material including molecularchains. Of the molecular chains, a number of molecular chains orientedin an orthogonal direction is larger than a number of molecular chainsoriented in a counter direction, the orthogonal direction beingorthogonal to the counter direction, and the counter direction is adirection in which the first glass panel and the second glass panel faceeach other.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view schematically illustrating a glass panel unitaccording to a first embodiment of the present disclosure;

FIG. 2 is a plan view schematically illustrating the glass panel unit;

FIG. 3A is an enlarged view illustrating an example of an internalcomposition of a resin material included in a spacer in the glass panelunit, FIG. 3B is an enlarged view illustrating another example of theinternal composition of the resin material included in the spacer in theglass panel unit, and FIG. 3C is an enlarged view illustrating stillanother example of the internal composition of the resin materialincluded in the spacer in the glass panel unit;

FIG. 4 is a perspective view illustrating a manufacturing process of theglass panel unit;

FIG. 5 is a perspective view illustrating the manufacturing process ofthe glass panel unit;

FIG. 6 is a perspective view illustrating the manufacturing process ofthe glass panel unit;

FIG. 7 is a perspective view illustrating the manufacturing process ofthe glass panel unit;

FIG. 8 is a plan view schematically illustrating an assembly for theglass panel unit;

FIG. 9 is a sectional view schematically illustrating the assembly forthe glass panel unit;

FIG. 10 is a perspective view illustrating the manufacturing process ofthe glass panel unit;

FIG. 11A is a side view illustrating a setting step of a spacerprovision step in the manufacturing process of the glass panel unit,FIG. 11B is a side view illustrating a spacer forming step of the spacerprovision step in the manufacturing process of the glass panel unit, andFIG. 11C is a side view illustrating a displacement step of the spacerprovision step in the manufacturing process of the glass panel unit;

FIG. 12 is a sectional view schematically illustrating a glass panelunit according to a second embodiment of the present disclosure; and

FIG. 13 is a front view illustrating an insulating glass windowincluding the glass panel unit.

DESCRIPTION OF EMBODIMENTS

The present disclosure relates to glass panel units and specifically, toa glass panel unit including a first glass panel and a second glasspanel facing each other and a seal and spacers disposed between thefirst glass panel and the second glass panel.

A glass panel unit of a first embodiment will be described withreference to the drawings.

FIGS. 1 and 2 show a glass panel unit 10. The glass panel unit 10 of thefirst embodiment is a vacuum insulating glass unit. The vacuuminsulating glass unit is a type of insulated glazing panels including atleast a pair of glass panels and includes a depressurized space 50between the pair of glass panels. Note that in FIG. 2, a part (lowerleft part) of a first glass panel 20 is cut away for ease ofunderstanding of the internal structure of the glass panel unit.

The glass panel unit 10 includes the first glass panel 20, a secondglass panel 30, a seal 40, a depressurized space 50, and spacers 70. Thesecond glass panel 30 is disposed to face the first glass panel 20. Theseal 40 has a frame shape and hermetically binds the first glass panel20 and the second glass panel 30 together. The depressurized space 50 issurrounded by the first glass panel 20, the second glass panel 30, andthe seal 40. The spacers 70 are disposed between the first glass panel20 and the second glass panel 30. In the first embodiment, the spacers70 contain polyimide having a benzoxazole structure. Note that thespacers 70 are not limited to spacers containing polyimide having abenzoxazole structure.

In the glass panel unit 10, the spacers 70 contain polyimide having abenzoxazole structure, and therefore, the strength of the spacers 70 isincreased. Moreover, the spacers 70 contain the polyimide having thebenzoxazole structure and are thus provided with elasticity. Moreover,the spacers 70 contain the polyimide having the benzoxazole structureand thus have increased heat resistance. Thus, the depressurized space50 is sufficiently formed, and the glass panel unit 10 which isresistant to external impacts is obtained.

The first glass panel 20 includes a body 21 and a coating 22. The body21 defines the planar shape of the first glass panel 20. The body 21 hasa rectangular shape and includes a first surface (outer surface; anupper surface in FIG. 1) and a second surface (inner surface; a lowersurface in FIG. 1) in a thickness direction thereof, and the firstsurface and the second surface are parallel to each other. Each of thefirst surface and the second surface of the body 21 is a flat surface.Examples of a material for the body 21 of the first glass panel 20include soda-lime glass, high strain-point glass, chemicallystrengthened glass, no-alkali glass, quartz glass, Neoceram, andphysically strengthened glass. Note that the first glass panel 20 doesnot have to include the coating 22.

The coating 22 is formed on the second surface of the body 21. Thecoating 22 is preferably an infrared reflective film. Note that thecoating 22 is not limited to the infrared reflective film but may be afilm having a desired physical property.

The second glass panel 30 includes a body 31 defining the planar shapeof the second glass panel 30. The body 31 has a rectangular shape andincludes a first surface (inner surface; an upper surface in FIG. 1) anda second surface (outer surface; a lower surface in FIG. 1) in athickness direction thereof, and the first surface and the secondsurface are parallel to each other. Each of the first surface and thesecond surface of the body 31 is a flat surface. Examples of a materialfor the body 31 of the second glass panel 30 include soda-lime glass,high strain-point glass, chemically strengthened glass, no-alkali glass,quartz glass, Neoceram, and physically strengthened glass. The materialfor the body 31 may be the same as the material for the body 21.

The second glass panel 30 includes only the body 31. The second glasspanel 30 may include a coating.

The first glass panel 20 and the second glass panel 30 are arranged suchthat the second surface of the body 21 and the first surface of the body31 are parallel to each other and face each other.

The thickness of the first glass panel 20 is not particularly limitedbut is within a range of, for example, 1 mm to 10 mm. The thickness ofthe second glass panel 30 is not particularly limited but is within arange of, for example, 1 mm to 10 mm.

In FIGS. 1 and 2, the glass panel unit 10 further includes a gasadsorbent 60. The gas adsorbent 60 is disposed in the depressurizedspace 50. In the first embodiment, the gas adsorbent 60 has an elongatedshape. The gas adsorbent 60 is disposed in any place in thedepressurized space 50.

The gas adsorbent 60 is used to adsorb unnecessary gas (remaining gasand the like). The unnecessary gas is, for example, gas released whenthe seal 40 is formed.

The gas adsorbent 60 includes a getter. The getter is a material havinga property of adsorbing molecules smaller than a prescribed size. Thegetter is, for example, an evaporable getter. Note that the evaporablegetter mentioned herein refers to a type of getter which desorbs gasmolecules adsorbed thereon to the outside when heated at a prescribedtemperature or higher for activation. The evaporable getter is, forexample, zeolite or ion-exchanged zeolite.

The seal 40 completely surrounds the depressurized space 50 andhermetically binds the first glass panel 20 and the second glass panel30 together. The seal 40 is disposed between the first glass panel 20and the second glass panel 30. The seal 40 has a rectangular frameshape. The depressurized space 50 has a degree of vacuum lower than orequal to a prescribed value. The prescribed value is, for example, 0.1Pa, and when the internal pressure is lower than or equal to a pressurewhich can be regarded as being vacuum, the depressurized space 50 is avacuum space.

The depressurized space 50 is created by being evacuated while heated.Heating increases the degree of vacuum. Moreover, the seal 40 is formedthrough heating.

The seal 40 is made of a thermal adhesive. The thermal adhesive is, forexample, glass frit. The glass frit is, for example, low-melting-pointglass frit. Examples of the low-melting-point glass frit includebismuth-based glass frit, lead-based glass frit, and vanadium-basedglass frit.

The glass panel unit 10 includes a plurality of spacers 70. Theplurality of spacers 70 are adopted to maintain a prescribed spacebetween the first glass panel 20 and the second glass panel 30. Thespacers 70 certainly secure the space between the first glass panel 20and the second glass panel 30. The number of the spacers 70 may be one,but in order to secure a sufficient thickness between the glass panels,two or more spacers 70 are preferably provided. Adopting the pluralityof spacers 70 increases the strength of the glass panel unit 10.

The plurality of spacers 70 are arranged in the depressurized space 50.Specifically, the plurality of spacers 70 are arranged at respectiveintersections of a virtual rectangular grid. For example, the pluralityof spacers 70 are arranged at a pitch within a range of 1 cm to 10 cm.The pitch may specifically be 2 cm. Note that the sizes, number, pitch,and arrangement pattern of the spacers 70 may be appropriately selected.

Each of the spacers 70 has a shape of a column which has a heightsubstantially equal to the prescribed space (space between the firstglass panel 20 and the second glass panel 30). For example, the spacers70 may have a diameter of 0.1 mm to 10 mm and a height of 10 μm to 1000μm. Specifically, the spacers 70 have a diameter of 0.5 mm and a heightof 100 μm. Note that each spacer 70 may have a desired shape such as aprism shape or a spherical shape. The height of the spacers 70 definesthe distance between the first glass panel 20 and the second glass panel30, that is, the thickness of the depressurized space 50. The thicknessof the depressurized space 50 may be, for example, 10 μm to 1000 μm. Thethickness of the depressurized space 50 is specifically 100 μm.

The spacers 70 are preferably made of a transparent material but do nothave to be made of the transparent material. When the spacers 70 aremade of the transparent material, the spacers 70 become lessperceivable. Note that when being sufficiently small, each spacer 70 maybe made of a non-transparent material. The material for the spacers 70is selected so that the spacers 70 do not deform in a first meltingstep, an evacuation step, and a second melting step which will bedescribed later.

The spacers 70 contain polyimide having a benzoxazole structure. Thepolyimide is a polymer having a structure defined by the followinggeneral formula (1).

In the formula (1), R and R′ independently denote an organic group, andn denotes an integer larger than or equal to 1.

The benzoxazole structure is introduced into the structure defined bythe general formula (1). The benzoxazole structure is preferablyintroduced into the organic group R′ in the general formula (1).Benzoxazole is defined by formula (2). Hydrogen in the benzoxazoledefined by the formula (2) is substituted with another element inpolyimide, and thereby, the benzoxazole structure is introduced into thepolyimide. Preferably, two or more hydrogen atoms are substituted,thereby introducing the benzoxazole structure into a main chain of thepolymer.

The polyimide having the benzoxazole structure may have a phenylbenzoxazole structure. Phenyl benzoxazole is defined by formula (3).Hydrogen in the phenyl benzoxazole defined by the formula (3) issubstituted by another element in the polyimide, thereby introducing thephenyl benzoxazole structure into the polyimide. Preferably, two or morehydrogen atoms are substituted, thereby introducing the phenylbenzoxazole structure into the main chain of the polymer.

The polyimide having the benzoxazole structure may have a phenylenebisbenzoxazole structure. Phenylene bisbenzoxazole is defined by formula(4). Hydrogen in the phenylene bisbenzoxazole defined by the formula (4)is substituted with another element in the polyimide, therebyintroducing the phenylene bisbenzoxazole structure into the polyimide.Preferably, two or more hydrogen atoms are substituted, therebyintroducing the phenylene bisbenzoxazole structure into the main chainof the polymer.

The polyimide having the benzoxazole structure may include a diphenylbenzobisoxazole structure. Diphenyl benzobisoxazole is defined byformula (5). Hydrogen in the diphenyl benzobisoxazole defined by theformula (5) is substituted with another element in the polyimide,thereby introducing the diphenyl benzobisoxazole structure into thepolyimide. Preferably, two or more hydrogen atoms are substituted,thereby introducing the diphenyl benzobisoxazole structure into the mainchain of the polymer.

The polyimide is obtained through polycondensation of diamines andtetracarboxylic anhydrides. The diamines are preferably aromaticdiamines. The tetracarboxylic anhydrides are preferably aromatictetracarboxylic anhydrides. Polyimide obtained by reaction of thearomatic diamines and the aromatic tetracarboxylic anhydrides with eachother is preferably adopted. The aromatic diamines preferably havebenzoxazole structures. Adopting the aromatic diamines having thebenzoxazole structures enables the benzoxazole structures to beintroduced into the polyimide.

Examples of the aromatic diamines having the benzoxazole structuresinclude a substance defined by any of the following formula (6), formula(7), and formula (8).

Examples of the aromatic diamines having the benzoxazole structuresspecifically include 5-amino-2-(p-aminophenyl)benzoxazole,6-amino-2-(p-aminophenyl)benzoxazole,5-amino-2-(m-aminophenyl)benzoxazole,6-amino-2-(m-aminophenyl)benzoxazole, 2,2-p-phenylenebis(5-aminobenzoxazole),1,5-(5-aminobenzoxazolo)-4-(5-aminobenzoxazolo)benzene,2,6-(4,4′-diaminodiphenyl)benzo[1,2-d:5,4-]bisoxazole,2,6-(4,4′-diaminodiphenyl)benzo[1,2-d:4,5-d′]bisoxazole,2,6-(3,4′-diaminodiphenyl)benzo[1,2-d:5,4-]bisoxazole,2,6-(3,4′-diaminodiphenyl)benzo[1,2-d:4,5-d′]bisoxazole,2,6-(3,3′-diaminodiphenyl)benzo[1,2-d:5,4-]bisoxazole, and2,6-(3,3′-diaminodiphenyl)benzo[1,2-d:4,5-d′]bisoxazole.

One of these aromatic diamines may be adopted alone, or two or more ofthese aromatic diamines may be adopted together.

Examples of the aromatic tetracarboxylic anhydrides include pyromelliticdianhydride, 3,3′,4,4′-biphenyl tetracarboxylic anhydride,4,4′-oxydiphthalic anhydride, 3,3′,4,4′-benzophenone tetracarboxylicanhydride, 3,3′,4,4′-diphenyl sulfone tetracarboxylic anhydride, and2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanoic anhydride.

One of these aromatic tetracarboxylic anhydrides may be adopted alone,or two or more of these aromatic tetracarboxylic anhydrides may beadopted together.

In the known art, metal has been widely used as the spacers of the glasspanel unit (see, for example, Patent Literature 1, [0017]). However,metal generally has too high thermal conductivity to achieve thermalinsulation advantageously. A resin with high strength could be adoptedas a material for the spacers, but the resin with high strength hasgenerally high density and thus has high thermal conductivity andinsufficient thermal insulation. Moreover, metal has low elasticity andhardly absorb impacts, and therefore, the glass panel unit becomesvulnerable to impact. Moreover, glass or ceramic could be used as amaterial for the spacers (see Patent Literature 1, [0026] <4>). In thiscase, however, the strength would tend to decrease. As described above,in the case of an ordinary material (material having no anisotropy ofthe thermal conductivity), it is difficult to realize high strength andlow thermal conductivity (in other words, both the thermal insulationproperty and the impact resistance).

Note that a thermal conductivity required for the spacers 70 is that thethermal conductivity (unit: W/(m·K)) is low in a counter direction 91 inwhich the first glass panel 20 and the second glass panel 30 face eachother.

Moreover, the strength required for the spacers 70 is mainly compressivestrength. When the spacers 70 are compressed in the counter direction91, the spacers 70 deforms to reduce the dimension thereof in thecounter direction 91, and simultaneously, the dimension of the spacers70 in orthogonal directions 92 orthogonal to the counter direction 91increases.

In general, heat is easily transferred in a direction in which chemicalbinding of molecules forms molecular chains, and the heat is hardlytransferred between molecular chains. Moreover, when curved molecularchains are straightened, a macromolecular material deforms. Therefore,when directions of the molecular chains are not fixed, themacromolecular material easily deforms. The spacers 70 are continuouslycompressed by atmospheric pressure. Therefore, when directions ofmolecular chains 71 (see FIGS. 3A to 3C) are not fixed, creepdeformation is more likely caused by long-term use, and thus,morphological stability is degraded. Moreover, when the macromolecularmaterial is subjected to a heavy load and deforms, the molecular chains71 which are tangled may be broken if the directions of the molecularchains 71 are not fixed. Thus, also from the point of view of thestrength and morphological stability, it is preferable that in thespacers 70, the directions of the molecular chains 71 correspond to theorthogonal direction 92.

Thus, when the directions of the molecular chains 71 of the spacer 70are set to correspond to the orthogonal direction 92, it is possible torealize high strength and a low thermal conductivity (in other words,both thermal insulation property and impact resistance).

In the first embodiment, as illustrated in FIG. 1, the spacers 70 aremade of a material whose thermal conductivity in the counter direction91 of the first glass panel 20 and the second glass panel 30 is lowerthan the thermal conductivity in the orthogonal direction 92 withrespect to the counter direction 91.

With this configuration, adopting a special material having anisotropyof the thermal conductivity reduces the thermal conductivity in thecounter direction 91 of the first glass panel 20 and the second glasspanel 30 as much as possible while easily securing the impactresistance.

In particular, in the first embodiment, the spacers 70 include amacromolecular resin material including the molecular chains 71. Themolecular chains 71 have an orientation in which an elongation direction73 (see FIG. 3C) corresponds to the orthogonal direction 92.

With this configuration, a resin material having anisotropy of thethermal conductivity is adopted to reduce only the thermal conductivityin the counter direction 91 of the first glass panel 20 and the secondglass panel 30, and thus, the impact resistance is easily secured. Inthe first embodiment, the polyimide provides the spacers 70 with highstrength. The spacers 70 have elasticity and improve the impactresistance of the glass panel unit 10. The spacers 70 are heat-resistantand less likely to be destroyed. The spacers 70 have low thermalconductivity and improve a thermal insulation property.

FIG. 3A shows an enlarged view of an example of an internal compositionof a resin material included in the spacers 70. In the resin materialillustrated in FIG. 3A, the molecular chains 71 have no directionalproperty (orientation) and thus have no anisotropy of the thermalconductivity. Moreover, the resin material included in the spacers 70includes no crystal part. The resin material shown in FIG. 3A is notsuitable as a resin material included in the spacers 70.

FIG. 3B shows an enlarged view of another example of the internalcomposition of the resin material included in the spacers 70. In theresin material shown in FIG. 3B, the molecular chains 71 have nodirectional property (orientation) and thus have no anisotropy of thethermal conductivity. However, the resin material included in thespacers 70 includes a crystal part (microcrystals, that is, crystallites72). In the crystallites 72, the molecular chains 71 are bound togetherwith strong binding force. Thus, when compared with the spacers 70including the resin material shown in FIG. 3A, the spacers 70 includingthe resin material shown in FIG. 3B has a high strength and high impactresistance. The resin material shown in FIG. 3B is also not suitable asa resin material included in the spacers 70.

FIG. 3C shows an enlarged view of still another example of the internalcomposition of the resin material included in the spacers 70. In theresin material shown in FIG. 3C, the molecular chains 71 have adirectional property (orientation) and thus have anisotropy of thethermal conductivity. When in the resin material shown in FIG. 3C, thedirection in which the molecular chains 71 are oriented is defined asthe elongation direction 73, the spacers 70 including the resin materialshown in FIG. 3C are arranged such that the elongation direction 73 isoriented in the orthogonal direction 92.

The elongation direction 73 is adjusted such that when the resinmaterial is elongated to be in a seat-like shape, the molecular chains71 are oriented in the elongation direction of the seat.

Moreover, the resin material shown in FIG. 3C has crystallites 72, andthe spacers 70 including the resin material shown in FIG. 3C have highstrength and high resistance. The resin material shown in FIG. 3C issuitable as the resin material for forming the spacers 70.

A method for providing the spacers 70 with the orientation of themolecular chains 71 may be but is not particularly limited to a methodof elongating a macromolecular film in the orthogonal direction 92, amethod of forming the spacers 70 by so-called spin-coating, a method ofrolling a macromolecular film, a method of pressing the macromolecularfilm, or the like.

The spacers 70 are preferably made of polyimide whose viscoelasticcoefficient at 400° C. is higher than 500 MPa. Thus, the glass panelunit 10 with high strength is obtained. The viscoelastic coefficient ofthe polyimide at 400° C. may be lower than 1×10⁶ MPa. The viscoelasticcoefficient of the polyimide at 400° C. is preferably higher than 1000MPa, more preferably higher than 1500 MPa, and much more preferablyhigher than 2000 MPa. The viscoelastic coefficient is measured by aviscoelastic measuring device. Examples of the viscoelastic measuringdevice include a dynamic mechanical analysis (DMA) device and athermomechanical analysis (TMA) device. In polyimide contained in thespacers 70, the ratio of a viscoelastic coefficient V400 at 400° C. to aviscoelastic coefficient V20 at 20° C. (V400/V20) is preferably higherthan or equal to 0.1. This ratio (V400/V20) is more preferably higherthan or equal to 0.2, much more preferably higher than or equal to 0.3,and much more preferably higher than or equal to 0.4. The spacers 70 arepreferably made of polyimide whose thermal expansion coefficient at 400°C. is lower than 10 ppm/° C. Thus, the glass panel unit 10 with highstrength is obtained. The thermal expansion coefficient of the polyimideat 400° C. may be higher than 0.1 ppm/° C. The thermal expansioncoefficient is measured with a thermal expansion coefficient measuringdevice. Examples of the thermal expansion measuring device include athermomechanical analysis (TMA) device. The spacers 70 are morepreferably made of polyimide whose viscoelastic coefficient at 400° C.is higher than 500 MPa and whose thermal expansion coefficient at 400°C. is lower than 10 ppm/° C.

In this embodiment, the spacers 70 are preferably formed of at least onelayer of polyimide film. Using the polyimide film facilitates formationof the spacers 70. The polyimide film is cut in the shape of the spacers70 and used as the spacers 70.

In this embodiment, a method of elongating the macromolecular film inorthogonal directions 92 to provide the spacer 70 with the orientationof the molecular chains 71 will be described.

The macromolecular film may be elongated only in a first direction (oneof the orthogonal directions 92) in the plane thereof. Alternatively,the macromolecular film may be elongated in both the first direction anda second direction orthogonal to the first direction (the otherdirection of the orthogonal directions 92) in the plane thereof. As themacromolecular film, a polyimide film is preferably used, but themacromolecular film is not particularly limited to this example.

Thus, when a method of elongating a macromolecular film is adopted, anelongation ratio or a percentage elongation of the macromolecular film,that is, a ratio of the length of the macromolecular film afterelongation to the length of the macromolecular film before elongation ispreferably high as long as the macromolecular film is not broken.

The elongation ratio in the first direction and the elongation ratio inthe second direction are independent of each other. Thus, when themacromolecular film is elongated in both the first direction and thesecond direction, the elongation ratio in the first direction and theelongation ratio in the second direction may be different from eachother. When the elongation ratio in the first direction and theelongation ratio in the second direction are different from each other,the highest possible elongation ratio can be achieved, and it ispossible to further increase the compressive strength and to furtherreduce the thermal conductivity in the counter direction 91.

Specifically, for example, the elongation ratio in the first directionmay be 1, and the elongation ratio in the second direction may be 2, 5,10, or a value higher than 10. Alternatively, for example, theelongation ratio in the first direction may be 2, and the elongationratio in the second direction may be 10. When the elongation ratio inthe first direction is 2, and the elongation ratio in the seconddirection is 10, the strength at a high temperature is higher than whenthe elongation ratio in the first direction is 4, and the elongationratio in the second direction is 4.

Note that a method for providing the spacers 70 with the orientation ofthe molecular chains 71 other than a method of elongating themacromolecular film in the orthogonal direction 92 will further bedescribed later.

The area ratio of the spacers 70 with respect to the glass panel unit 10in plan view is preferably within a range of 0.01% to 0.2%. Thus, it ispossible to make the spacers 70 less perceptible and to increase thestrength of the glass panel unit 10. As used herein “in plan view” meansviewing in a thickness direction of the glass panel unit 10. Thethickness direction of the glass panel unit 10 is equal to a heightdirection of the spacers 70.

With reference to FIGS. 4 to 10, a manufacturing method of the glasspanel unit 10 will be described. FIGS. 4 to 10 show an exemplarymanufacturing process of the glass panel unit 10. The glass panel unit10 shown in FIGS. 1 to 3 may be manufactured by the method shown inFIGS. 4 to 10. In the method illustrated in FIGS. 4 to 10, a glass panelunit 10 without an exhaust port is manufactured.

For the glass panel unit 10, a pre-assembled component 100 asillustrated in FIGS. 4 to 6 is obtained, and then, predeterminedprocesses are preformed to obtain an assembly 110 as illustrated inFIGS. 7 to 9. Thereafter, as illustrated in FIG. 10, a portion is cutoff from the assembly 110 to obtain the glass panel unit 10.

The manufacturing method of the glass panel unit 10 includes apreparation step, an assembling step, a hermetically sealing step, and aremoval step. Note that the preparation step may be omitted.

The preparation step is a step of preparing a first plate glass 200, asecond plate glass 300, a frame member 410, a partition 420, the gasadsorbent 60, and the plurality of spacers 70. In the preparation step,an inside space 500, an air passage 600, and an exhaust port 700 may beformed.

The first plate glass 200 is a plate glass used for the first glasspanel 20. As illustrated in FIG. 9, the first plate glass 200 includes aglass pane 210 and a coating 220. Note that the coating 220 may beomitted.

The second plate glass 300 is a plate glass used for the second glasspanel 30. As illustrated in FIG. 9, the second plate glass 300 includesa glass pane 310 defining the planar shape of the second plate glass300. The glass pane 310 is the second plate glass 300 itself.

The second plate glass 300 is disposed to face the first plate glass200.

The frame member 410 is disposed between the first plate glass 200 andthe second plate glass 300 and hermetically binds the first plate glass200 and the second plate glass 300 together. Thus, as illustrated inFIG. 6, the inside space 500 surrounded by the frame member 410, thefirst plate glass 200, and the second plate glass 300 is formed.

The frame member 410 is formed of a thermal adhesive (first thermaladhesive having a first softening point). The first thermal adhesive is,for example, glass frit. The glass frit is, for example,low-melting-point glass frit. Examples of the low-melting-point glassfrit include bismuth-based glass frit, lead-based glass frit, andvanadium-based glass frit.

The partition 420 is disposed in the inside space 500. As illustrated inFIG. 6, the partition 420 divides the inside space 500 into anevacuation space 510 and a vent space 520. The evacuation space 510 is aspace which will be evacuated later, and the vent space 520 is a spaceused for the evacuation of the evacuation space 510.

The partition 420 includes a wall section 421 and a pair of blockingsections 422 (a first blocking section 4221 and a second blockingsection 4222). The wall section 421 is formed along the width directionof the second plate glass 300. The width direction means a directionalong short sides of the pre-assembled component 100 having arectangular shape in FIG. 6. Note that both ends in a length directionof the wall section 421 are not in contact with the frame member 410.The pair of blocking sections 422 extends from both of the ends in thelength direction of the wall section 421 to a first end in a lengthdirection of the second plate glass 300.

The partition 420 is formed of a thermal adhesive (second thermaladhesive having a second softening point). The second thermal adhesiveis, for example, glass frit. The glass frit is, for example,low-melting-point glass frit. Examples of the low-melting-point glassfrit include bismuth-based glass frit, lead-based glass frit, andvanadium-based glass frit.

As illustrated in FIG. 4, the plurality of spacers 70 may be arranged atprescribed intervals in rows and columns.

Here, the height of the spacers 70 as a member before assembled into theglass panel unit 10 may be different from the height of the spacers 70after the glass panel unit 10 is formed. The spacers 70 may becompressed in the height direction by being sandwiched between two glasspanels. When the spacers 70 contain polyimide having a benzoxazolestructure, the strength of the spacers 70 is increased, and therefore,it is possible to suppress the spacers 70 from being too stronglycompressed. Thus, the thickness of the depressurized space 50 is easilysecured. Moreover, the strength of the glass panel unit 10 can beincreased. Moreover, the spacers 70 are suppressed from being destroyed,and the appearance (aesthetic property) of the glass panel unit 10 canbe improved.

The air passage 600 is in communication with the evacuation space 510and the vent space 520 in the inside space 500. The air passage 600includes a first air passage 610 and a second air passage 620. The firstair passage 610 is a space formed between the first blocking section4221 and a part of the frame member 410 facing the first blockingsection 4221. The second air passage 620 is a space formed between thesecond blocking section 4222 and a part of the frame member 410 facingthe second blocking section 4222.

The exhaust port 700 is a pore communicating with the vent space 520 andthe outside space. The exhaust port 700 is used to evacuate theevacuation space 510 through the vent space 520 and the air passage 600.

The members as described above are subjected to the preparation step.The preparation step includes a first to sixth steps. Note that theorder of the second to sixth steps may accordingly be changed.

The first step is a step (plate glass forming step) of forming the firstplate glass 200 and the second plate glass 300.

The second step is a step of forming the exhaust port 700. In the secondstep, the exhaust port 700 is formed in the second plate glass 300. Notethat the exhaust port 700 may be formed in the first plate glass 200.

The third step is a step (seal member forming step) of forming the framemember 410 and the partition 420. In the third step, a material (thefirst thermal adhesive) for the frame member 410 and a material (thesecond thermal adhesive) for the partition 420 are applied to the secondplate glass 300 (a first surface of the glass pane 310) with a dispenseror the like. Then, the material for the frame member 410 and thematerial for the partition 420 are dried and pre-sintered.

The fourth step is a step (spacer provision step) of providing thespacers 70. In FIGS. 11A to 11C, an example of the spacer provision stepis shown. The spacer provision step includes a setting step, a spacerforming step, and a displacement step sequentially.

In the setting step shown in FIG. 11A, the first glass panel 20, apunching die 81, a sheet material 82, and a punch section 83 are set inthis order from bottom to top. The sheet material 82 covers an uppersurface of the punching die 81. A punch 84 included in the punch section83 is located directly above a through hole 85 in the punching die 81with the sheet material 82 provided between the punch 84 and thepunching die 81.

In the spacer forming step shown in FIG. 11B, the punch section 83 isdriven downward along a linear track. The punch section 83 is drivendownward, thereby punching out a part 86 of the sheet material 82downward by the punch 84 having a columnar shape through the throughhole 85 in the punching die 81 (see the void arrow in FIG. 11B).

The part 86 of the sheet material 82 punched by the punch 84 is pressedonto one surface 87 of the first glass panel 20 with the part 86abutting a tip surface of the punch 84.

The part 86 of the sheet material 82 is pressed onto the one surface 87of the first glass panel 20 at a prescribed pressure for a predeterminedtime by the tip surface of the punch 84, thereby being prefixed to theone surface 87. The part 86 of the sheet material 82 thus prefixed isincluded in the spacer 70 on the one surface 87.

In the displacement step shown in FIG. 11C, as illustrated in the voidarrows, after the punch section 83 moves upward, the first glass panel20 and the sheet material 82 move in the horizontal direction. In thefirst embodiment, the travel direction of the first glass panel 20 andthe travel direction of the sheet material 82 are the same, but thetravel direction of the first glass panel 20 and the travel direction ofthe sheet material 82 may be different from each other.

The fourth step is as described above. Note that the fourth step is notlimited to the step described above.

The fifth step is a step (gas adsorbent forming step) of forming the gasadsorbent 60. In the fifth step, a solution in which powder of a getteris dispersed is applied at a predetermined location on the second plateglass 300 and is dried, thereby forming the gas adsorbent 60.

After the first step through the fifth step are completed, the secondplate glass 300 provided with the frame member 410, the partition 420,the air passage 600, the exhaust port 700, the gas adsorbent 60, and theplurality of spacers 70 as illustrated in FIG. 4 is obtained.

The sixth step is a step (disposition step) of disposing the first plateglass 200 and the second plate glass 300 (see FIG. 5). In the sixthstep, the first plate glass 200 and the second plate glass 300 aredisposed such that the second surface of the glass pane 210 and thefirst surface of the glass pane 310 are parallel to each other and faceeach other.

The assembling step is a step of preparing the pre-assembled component100.

Specifically, the assembling step is a step (first melting step) ofhermetically binding the first plate glass 200 and the second plateglass 300 together by the frame member 41.

In the first melting step, the first thermal adhesive is once melted ata predetermined temperature (first melting temperature) higher than orequal to the first softening point to hermetically bind the first plateglass 200 and the second plate glass 300 together. The first plate glass200 and the second plate glass 300 are hermetically bound together bythe frame member 410.

Through the assembling step (first melting step), the pre-assembledcomponent 100 shown in FIG. 6 is obtained. The pre-assembled component100 includes the first plate glass 200, the second plate glass 300, theframe member 410, the inside space 500, the partition 420, the airpassage 600, the exhaust port 700, the gas adsorbent 60, and theplurality of spacers 70.

The hermetically sealing step is a step of performing the predeterminedprocesses on the pre-assembled component 100 to obtain the assembly 110.The hermetically sealing step includes an evacuation step and a meltingstep (second melting step). That is, the evacuation step and the secondmelting step correspond to the predetermined processes.

The evacuation step is a step of evacuating the evacuation space 510 ata predetermined temperature (evacuation temperature) through the airpassage 600, the vent space 520, and the exhaust port 700 to create thedepressurized space 50.

The evacuation is performed with, for example, a vacuum pump. Asillustrated in FIG. 6, the vacuum pump is connected to the pre-assembledcomponent 100 via an exhaust pipe 810 and a seal head 820. The exhaustpipe 810 is bound to the second plate glass 300, for example, such thatthe interior of the exhaust pipe 810 is in communication with theexhaust port 700.

The first melting step, the evacuation step, and the second melting stepare performed with the first plate glass 200 and the second plate glass300 being placed in a melting furnace.

The second melting step is a step of deforming the partition 420 to forma partition 42 closing the air passage 600 to form the seal 40surrounding the depressurized space 50. In the second melting step, thesecond thermal adhesive is once melted at a predetermined temperature(second melting temperature) higher than or equal to the secondsoftening point to deform the partition 420, thereby forming thepartition 42.

When the partition 42 is formed, the depressurized space 50 is separatedfrom the vent space 520. Thus, the depressurized space 50 can no longerbe evacuated by the vacuum pump. Until the second melting step iscompleted, the frame member 410 and the partition 42 are heated, andtherefore, gas may be released from the frame member 410 and thepartition 42. However, the gas released from the frame member 410 andthe partition 42 is adsorbed by the gas adsorbent 60 in thedepressurized space 50. This prevents degradation of the degree ofdepressurization (degree of vacuum) in the depressurized space 50.

The partition 420 is deformed such that the first blocking section 4221closes the first air passage 610, and the second blocking section 4222closes the second air passage 620. The partition 42 obtained by thusdeforming the partition 420 (spatially) separates the depressurizedspace 50 from the vent space 520. The partition (second section) 42 anda section (first section) 41 of the frame member 410 corresponding tothe depressurized space 50 form the seal 40 surrounding thedepressurized space 50.

Thus, the depressurized space 50 is created by evacuating the evacuationspace 510 through the vent space 520 and the exhaust port 700.

The first section 41 is a section of the frame member 410 correspondingto the depressurized space 50. The second section 42 is I-shaped and isa remaining one side of the four sides of the seal 40.

In the evacuation step, force is generated in a direction in which thefirst plate glass 200 and the second plate glass 300 approach eachother. At this time, the spacers 70 secure the space between the firstplate glass 200 and the second plate glass 300.

The hermetically sealing step provides the assembly 110 illustrated inFIGS. 7 to 9. The assembly 110 includes the first plate glass 200, thesecond plate glass 300, the seal 40, the depressurized space 50, thevent space 520, the gas adsorbent 60, and the plurality of spacers 70.In FIG. 8, a part (lower right part) of the first plate glass 200 is cutaway for ease of understanding the internal structure of the glass panelunit.

The removal step is a step of removing a part 11 including the ventspace 520 from the assembly 110 to obtain the glass panel unit 10 whichis a part including the depressurized space 50. As illustrated in FIG.8, specifically, the assembly 110 taken out of the melting furnace iscut along a cutting line 900 to be divided into a predetermined part(glass panel unit) 10 including the depressurized space 50 and a part(unnecessary part) 11 including the vent space 520. FIG. 10 shows howthe unnecessary part 11 is removed from the assembly 110.

The cutting is performed by any cutting device. Examples of the cuttingdevice include a scriber and a laser.

Through the above-described preparation step, assembling step,hermetically sealing step, and removal step, the glass panel unit 10 asillustrated in FIGS. 1 and 2 is obtained.

Next, a method for providing the spacer 70 with the orientation of themolecular chains 71 other than the method of elongating themacromolecular film in the orthogonal direction 92 will further bedescribed.

As a first example is referable a method of compressing spacers 70 eachhaving a columnar shape and containing a macromolecular material whileheating to arrange the spacers 70 on the first glass panel 20 or thesecond glass panel 30.

In the first example, the spacers 70 containing a macromolecularmaterial and having a columnar shape with a diameter of 599 μm wereobtained by a process of maintaining at 450° C. for 15 minutes whilecompression force of 40 N was applied. A destructive test was performedon the spacers 70 of the first example and spacers 70 as a comparativeexample having a columnar shape with a diameter of 541 μm and containinga macromolecular material without having been subjected to theabove-described processes. Table 1 shows the breaking load and thebreaking stress of the spacers 70 of the first example and the spacers70 of the comparative example.

TABLE 1 Diameter Breaking Load Breaking Stress (μm) (N) (MPa) FirstExample 599 180 643 Comparative 541 136 586 Example

Table 1 shows that the compressive strength (breaking stress) of thespacers 70 of the first example is higher than that of the spacers 70 ofthe comparative example.

A second example will be described. In manufacturing of a glass panelunit 10, spacers 70 are placed on a first glass panel 20 or a secondglass panel 30 (in the spacer provision step), and a frame member 410and a partition 420 are formed on the first glass panel 20 or the secondglass panel 30 (in the seal member forming step). Thereafter, the firstglass panel 20 and the second glass panel 30 are hermetically bound by aframe member 41, thereby forming a pre-assembled component 100 (in theassembling step), and then, an evacuation space 510 of the pre-assembledcomponent 100 is evacuated (in the evacuation step). In the evacuationstep, the first glass panel 20 and the second glass panel 30 aresubjected to atmospheric pressure, and therefore, the spacers 70 arecompressed in a counter direction 91 and extend in an orthogonaldirection 92. At this time, the evacuation temperature is increased toor higher than a temperature at which a resin contained in the spacers70 is plastically deformed, and thereby, the resin is plasticallydeformed, and a large number of molecular chains 71 are oriented in theorthogonal direction 92. Moreover, in this case, the resin isplastically deformed and the molecular chains 71 easily move, andtherefore, the molecular chains 71 which are tangled are less likely tobe broken.

The spacers 70 thus formed have high compressive strength, andtherefore, the spacers 70 are less likely to be broken when an impactload is applied to the first glass panel 20 or the second glass panel30.

Moreover, as a third example, a method of patterning paste containing amacromolecular material on a first glass panel 20 or a second glasspanel 30 by screen printing or a wet process with a dispenser or thelike and then drying and curing the paste thus patterned is referable.

Moreover, the orientation of the molecular chains 71 is not necessarilyprovided through a step of intentionally providing the orientation. Theorientation may be provided by, for example, elongating a film by usingheat shrinkage which occurs during film formation by a casting method orthe like. That is, a method for providing the orientation is notparticularly limited to the above-described examples as long as theratio of the molecular chains 71 oriented in the orthogonal direction 92is consequently higher than that of the molecular chains 71 oriented inthe counter direction 91.

Note that the ratio of the molecular chains 71 oriented in the counterdirection 91 to the molecular chains 71 oriented in the orthogonaldirection 92 does not have to be 0:1.

Moreover, the ratio of the thermal conductivity in the orthogonaldirection 92 to the thermal conductivity in the counter direction 91 ispreferably higher than or equal to, for example, 1.5, more preferablyhigher than or equal to 2, and much more preferably higher than or equalto 5.

With reference to FIGS. 12 and 13, a second embodiment will bedescribed. Note that the second embodiment includes components inaddition the components of the first embodiment, and therefore,components corresponding to those in the first embodiment are denoted bythe same reference signs as those in the first embodiment with “A” atthe end, the description thereof is omitted, and different componentsare mainly described.

As illustrated in FIG. 12, a glass panel unit 10A in the secondembodiment includes a third glass panel 93A disposed on a side of one ofa first glass panel 20A and a second glass panel 30A which is not incontact with a depressurized space 50A. The glass panel unit 10Aincludes a second seal 94A which has a frame shape and hermeticallybinding the third glass panel 93A and the first glass panel 20A or thesecond glass panel 30A which faces the third glass panel 93A. The glasspanel unit 10A includes a second inside space 95A surrounded by thethird glass panel 93A, the first glass panel 20A or the second glasspanel 30A which faces the third glass panel 93A, and the second seal94A.

The second inside space 95A may be a depressurized space (including avacuum space) similar to the depressurized space 50A or may be a spacefilled with gas.

Moreover, as illustrated in FIG. 13, the glass panel unit 10A may be fitin a window frame 96A to form an insulating glass window 97A.

The glass panel unit 10A of the second embodiment provides a furtherimproved thermal insulation property. Moreover, the second embodimentprovides the insulating glass window 97A having a further improvedthermal insulation property.

Thus, as can be seen from the first embodiment and the second embodimentdescribed above, a glass panel unit 10 of a first aspect according tothe present disclosure includes: a first glass panel 20 including atleast a glass pane 210; and a second glass panel 30 disposed to face thefirst glass panel 20. The second glass panel 30 includes at least glasspane 310. The glass panel unit 10 includes: a seal 40 having a frameshape and hermetically binding the first glass panel 20 and the secondglass panel 30 together; and a depressurized space 50 surrounded by thefirst glass panel 20, the second glass panel 30, and the seal 40. Theglass panel unit 10 includes a spacer 70 disposed between the firstglass panel 20 and the second glass panel 30.

The spacer 70 contains a macromolecular resin material includingmolecular chains 71. Of the molecular chains 71, the number of molecularchains 71 oriented in an orthogonal direction 92 is larger than thenumber of molecular chains 71 oriented in a counter direction 91. Theorthogonal direction 92 is orthogonal to the counter direction 91, andthe counter direction 91 is a direction in which the first glass panel20 and the second glass panel 30 face each other.

According to the first aspect, it is possible to reduce only the thermalconductivity in the counter direction 91 of the first glass panel 20 andthe second glass panel 30. Thus, it is possible to realize increasedstrength and a low thermal conductivity of the spacer 70 (in otherwords, both the thermal insulation property and the impact resistancecan be realized).

A second aspect according to the present disclosure is realized incombination with the first aspect. In the second aspect, the spacer 70is formed of a macromolecular film elongated in the orthogonal direction92. A normal direction to a surface of the macromolecular filmcorresponds to the counter direction 91. An elongation ratio of thespacer 70 in a first direction orthogonal to the counter direction 91 isdifferent from an elongation ratio of the spacer 70 in a seconddirection orthogonal to the counter direction 91 and the firstdirection.

According to the second aspect, without making the elongation ratio inthe first direction and the elongation ratio in the second directionequal to each other, the highest possible elongation ratio can beachieved, and it is possible to further increase the compressivestrength and to further reduce the thermal conductivity in the counterdirection 91.

A third aspect is realized in combination with the first aspect or thesecond aspect. In the third aspect, the elongation ratio of the spacer70 in at least one of the first direction and the second direction ishigher than or equal to 5.

According to the third aspect, it is possible to further increase thecompressive strength of the spacer 70 and to further reduce the thermalconductivity in the counter direction 91.

A fourth aspect is realized in combination with any one of the first tothird aspects. In the fourth aspect, in a step of elongating themacromolecular film serving as the spacer 70 in the orthogonal direction92, the macromolecular film is elongated at a temperature higher than orequal to a softening point of at least the seal 40.

According to the fourth aspect, a resin included in the spacer 70 ismore likely to be plastically deformed, and a large number of molecularchains 71 are more easily oriented in the orthogonal direction 92.

Moreover, the macromolecular film is elongated at a temperature higherthan or equal to the softening point of the seal 40 in advance.Therefore, the spacer 70 is more likely to maintain high orientationeven after the heat processing step subsequently performed on the glasspanel unit.

Note that as the temperature at the time of providing the molecularchains 71 of the spacer 70 with orientation, for example, in a step ofelongating the spacer 70 increases, the ratio of the molecular chains 71oriented in the orthogonal direction 92 to the molecular chains 71oriented in the counter direction 91 increases.

A fifth aspect is realized in combination with any one of the first tofourth aspects. In the fifth aspect, in an evacuation step of evacuatingan evacuation space 510 of a pre-assembled component 100 formed byhermetically binding the first glass panel 20 and the second glass panel30 by the frame member 41, the spacer 70 is sandwiched between the firstglass panel 20 and the second glass panel 30 under influence ofatmospheric pressure, and a macromolecular resin material included inthe spacer 70 is plastically deformed by a heating process.

According to the fifth aspect, the spacer 70 is compressed in thecounter direction 91 and extend in the orthogonal direction 92, and theresin included in the spacers 70 is plastically deformed, thereby alarge number of molecular chains 71 are oriented in the orthogonaldirection 92.

A sixth aspect is realized in combination with the fifth aspect. In thesixth aspect, a temperature of the heating process in the evacuationstep is higher than or equal to a glass-transition temperature of themacromolecular resin material included in the spacer 70.

According to the sixth aspect, the resin included in the spacer 70 isplastically deformed significantly, and thus, much more molecular chains71 are oriented in the orthogonal direction 92.

Moreover, the softening point of the seal 40 is preferably lower than orequal to the glass-transition temperature of the macromolecular resinmaterial of the spacer 70. Thus, degradation of the orientation of themolecular chains 71 can be suppressed.

REFERENCE SIGNS LIST

-   -   10 Glass Panel Unit    -   20 First Glass Panel    -   30 Second Glass Panel    -   40 Seal    -   50 Depressurized Space    -   70 Spacer    -   71 Molecular Chain    -   73 Elongation Direction    -   91 Counter Direction    -   92 Orthogonal Direction

1. A glass panel unit, comprising: a first glass panel including atleast a glass pane; a second glass panel disposed to face the firstglass panel, the second glass panel including at least glass pane; aseal having a frame shape and hermetically binding the first glass paneland the second glass panel together; a depressurized space surrounded bythe first glass panel, the second glass panel, and the seal; and aspacer disposed between the first glass panel and the second glasspanel, wherein the spacer contains a macromolecular resin materialincluding molecular chains, and of the molecular chains, a number ofmolecular chains oriented in an orthogonal direction is larger than anumber of molecular chains oriented in a counter direction, theorthogonal direction being orthogonal to the counter direction, thecounter direction being a direction in which the first glass panel andthe second glass panel face each other.
 2. The glass panel unitaccording to claim 1, wherein the spacer is formed of a macromolecularfilm elongated in the orthogonal direction, a normal direction to asurface of the macromolecular film corresponding to the counterdirection, an elongation ratio of the spacer in a first directionorthogonal to the counter direction being different from an elongationratio of the spacer in a second direction orthogonal to the counterdirection and the first direction.
 3. The glass panel unit according toclaim 1, wherein an elongation ratio of the spacer in at least one of afirst direction and a second direction is larger than or equal to
 5. 4.The glass panel unit accordingly to claim 2, wherein an elongation ratioof the spacer in at least one of a first direction and a seconddirection is larger than or equal to 5.